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Perfluoroarylation of Iron(II) Di‐ and Hexaiodoclathrochelates – Synthesis, X‐ray Structure, and Properties of the First Cage Complexes with Inherent Pentafluorophenyl Substituent(s)
Author(s) -
Varzatskii Oleg A.,
Denisenko Iri.,
Volkov Sergey V.,
Belov Alexander S.,
Dolganov Alexander V.,
Vologzhanina Anna V.,
Novikov Valentin V.,
Bubnov Yurii N.,
Voloshin Yan Z.
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201300189
Subject(s) - chemistry , steric effects , substituent , crystallography , trigonal prismatic molecular geometry , cyclic voltammetry , metal , stereochemistry , crystal structure , electrochemistry , organic chemistry , octahedron , electrode
Perfluoroarylation of a known iron(II) diiodoclathrochelate precursor and its new n ‐butylboron‐capped hexaiodomacrobicyclic analog with pentafluorophenylcopper(I) gave the first iron(II) cage complexes with inherent perfluoroaryl substituent(s). The complexes synthesized were characterized by elemental analysis, MALDI‐TOF mass spectrometry, IR, UV/Vis, 1 H, 11 B, 19 F, and 13 C{ 1 H} NMR spectroscopy, and X‐ray crystallography. The encapsulated iron(II) ions in the X‐rayed hexaiodo‐ and di‐ and hexa(pentafluorophenyl)ated iron(II) clathrochelates are located almost in the centers of their FeN 6 coordination polyhedra. The geometry of the hexaiodoclathrochelate precursor is trigonal prismatic (TP, distortion angle φ = 4.5°), whereas the perfluoroarylated iron(II) clathrochelates are intermediate between a TP and a trigonal antiprism (TAP) ( φ ≈ 25°). This rotation and expansion from TP to TAP polyhedra causes horizontal spreading, and the heights h decrease from 2.40 to 2.33–2.35 Å. Anodic ranges of the cyclic voltammograms (CVs) for the pentafluorophenylated iron(II) clathrochelates contain one‐electron waves of the metal‐centered Fe 2+/3+ oxidation, which are quasireversible in the cyclic voltammetry (CV) timescale. The potentials for the mono‐ and difunctionalized clathrochelates are only slightly different, as a result of steric hindrance between two pentafluorophenyl substituents in the same chelate ribbed fragment decreasing their conjugation with the polyazomethine clathrochelate framework and lowering the electronic effects. The cathodic ranges of these CVs contain irreversible waves for encapsulated metal‐centered Fe 2+/+ reduction to anionic forms of the cage complexes that are unstable on the CV timescale.